Clinico-pathological findings in cattle exposed to chronic bracken fern toxicity

Authors: Sardon D, Rodriguez-Bertos A, Blanco J, Perez-Alenza MD, Sanchez Moreiro MA
Publication: New Zealand Veterinary Journal, Volume 54, Issue 4, pp 185-192, Aug 2006
Publisher: Taylor and Francis

Animal type: Cattle, Livestock, Production animal, Ruminant
Subject Terms: Toxicology, Poisoning - plant, Circulatory system/haematology, Clinical pathology, Diagnostic procedures, Neoplasia, Oncology, Pathology, Urinary system/urology
Article class: Scientific Article

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Abstract: AIM: To describe changes in blood and urine analytes in a large group of cattle exposed to chronic bracken fern toxicity, in order to identify parameters of potential diagnostic value.
METHODS: The study was conducted on two livestock farms on which bovine enzootic haematuria (BEH) was known to occur; Farm A grazed a local breed of cows and Farm B grazed Friesians. Group A1 comprised 66 cows from Farm A, Group B 54 cows from Farm B, and Group A2 13 heifers from Farm A. Ten healthy cows were used as controls. A complete physical examination was performed (Group A1), and blood (all groups) and urine (Groups A1 and B) samples were collected. Necropsies and histopathology were undertaken on four cows.
RESULTS: Anaemia, leucopenia, monocytosis, thrombocytopenia, hypergammaglobulinaemia, microhaematuria and proteinuria were detected. Multivariate statistical analyses established three phases of the disease of increasing severity; an initial phase, characterised by an extremely high monocytosis and otherwise normal parameters; an intermediate phase, characterised by monocytosis and moderate changes to other analytes; and a final phase, characterised by normal levels of monocytes and many changes to other analytes.
CONCLUSIONS AND CLINICAL RELEVANCE: Monocytosis, detected in 31% of the younger animals, could represent an initial response to consumption of bracken fern and might be useful as an early haematological marker of BEH.
KEY WORDS: Bovine enzootic haematuria, bracken fern, clinical phases, monocytosis, urinary bladder tumours, multivariate analysis

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